How can I use VBScript to determine whether I am running a 32-bit or 64-bit Windows OS?

Came up against this same problem at work the other day. Stumbled on this genius piece of vbscript and thought it was too good not to share.

Bits = GetObject("winmgmts:root\cimv2:Win32_Processor='cpu0'").AddressWidth

Source: http://csi-windows.com/toolkit/csi-getosbits

You can query the PROCESSOR_ARCHITECTURE. A described here, you have to add some extra checks, because the value of PROCESSOR_ARCHITECTURE will be x86 for any 32-bit process, even if it is running on a 64-bit OS. In that case, the variable PROCESSOR_ARCHITEW6432 will contain the OS bitness. Further details in MSDN.

Dim WshShell
Dim WshProcEnv
Dim system_architecture
Dim process_architecture

Set WshShell =  CreateObject("WScript.Shell")
Set WshProcEnv = WshShell.Environment("Process")

process_architecture= WshProcEnv("PROCESSOR_ARCHITECTURE") 

If process_architecture = "x86" Then    
    system_architecture= WshProcEnv("PROCESSOR_ARCHITEW6432")

    If system_architecture = ""  Then    
        system_architecture = "x86"
    End if    
Else    
    system_architecture = process_architecture    
End If

WScript.Echo "Running as a " & process_architecture & " process on a " _ 
    & system_architecture & " system."

Here is a pair of VBScript functions based on the very concise answer by @Bruno:

Function Is32BitOS()
    If GetObject("winmgmts:root\cimv2:Win32_Processor='cpu0'").AddressWidth _
       = 32 Then
        Is32BitOS = True
    Else
        Is32BitOS = False
    End If
End Function

Function Is64BitOS()
    If GetObject("winmgmts:root\cimv2:Win32_Processor='cpu0'").AddressWidth _
       = 64 Then
        Is64BitOS = True
    Else
        Is64BitOS = False
    End If
End Function

UPDATE: Per the advice from @Ekkehard.Horner, these two functions can be written more succinctly using single-line syntax as follows:

Function Is32BitOS() : Is32BitOS = (GetObject("winmgmts:root\cimv2:Win32_Processor='cpu0'").AddressWidth = 32) : End Function

Function Is64BitOS() : Is64BitOS = (GetObject("winmgmts:root\cimv2:Win32_Processor='cpu0'").AddressWidth = 64) : End Function

(Note that the parentheses that surround the GetObject(...) = 32 condition are not necessary, but I believe they add clarity regarding operator precedence. Also note that the single-line syntax used in the revised implementations avoids the use of the If/Then construct!)

UPDATE 2: Per the additional feedback from @Ekkehard.Horner, some may find that these further revised implementations offer both conciseness and enhanced readability:

Function Is32BitOS()
    Const Path = "winmgmts:root\cimv2:Win32_Processor='cpu0'"
    Is32BitOS = (GetObject(Path).AddressWidth = 32)
End Function

Function Is64BitOS()
    Const Path = "winmgmts:root\cimv2:Win32_Processor='cpu0'"
    Is64BitOS = (GetObject(Path).AddressWidth = 64)
End Function